In 3GPP (3rd Generation Partnership Project) which is a standardization project, standardization of Evolved Universal Terrestrial Radio Access (hereinafter referred to as EUTRA) is performed, in which high speed communication is realized by adopting an OFDM (Orthogonal Frequency-Division Multiplexing) communication scheme and flexible scheduling with a predetermined frequency and time unit called a resource block.
Moreover, in the 3GPP, a discussion on Advanced EUTRA that realizes higher-speed data transmission and has a backward compatibility with the EUTRA has been carried out. In the EUTRA, a network in which base station apparatuses are composed of substantially the same cell configurations (cell sizes) is mainly premised, but in the Advanced EUTRA, a network (Heterogeneous Network) in which base station apparatuses (cells) having different configurations are mixed in the same area is premised, and a discussion has been carried out on a communication system corresponding thereto.
In a communication system in which cells (macro cells) having a large cell radius and cells (small cells) having a smaller cell radius than that of the macro cells coexist like the heterogeneous network, a technique that a terminal apparatus performs communication by connecting to a plurality of cells at the same time (dual connectivity) is being discussed (NPL 1).
Discussed in NPL 1 is dual connectivity between cells having the same frequency (co-channel scenario), as one of scenarios when a terminal apparatus realizes dual connectivity between a cell (macro cell) having a large cell radius (cell size) and a cell (small cell) having a small cell radius.
NPL 2 points out that when performing dual connectivity between cells having the same frequency, a terminal apparatus is difficult to uniquely determine a cell serving as a reference, for each of measurement events.